1. Field of the Invention
This invention relates to ink jet printers and particularly to an ink jet printer which prints lines of characters or other data patterns on a print medium. While not expressly limited thereto, this invention has particular application to an ink jet printer which uses magnetic ink.
2. Description of the Prior Art
In serial ink jet line printers a print head is moved across a line of a stationary print medium to print characters or other data patterns in the form of a dot matrix. The print head comprises means for propelling a continuous stream of individual ink drops on a fixed trajectory toward the print medium. A first deflection means deflects selected drops not used for printing in a direction parallel to the direction of motion to an ink collector positioned on one side of and closely adjacent to the ink jet stream. A second deflection means deflects the ink drops transverse to the direction of motion for deposition on the print medium to form characters. In order to obtain uniform character spacing and quality, printing occurs only when the head is moving at substantially uniform velocity. In order to achieve high printing speeds, the print head is rapidly accelerated to the uniform velocity and again rapidly decelerated to a stop. During the acceleration and deceleration phases of motion, the unused drops are being deflected by the first deflection means toward the drop collector. The rapid acceleration and deceleration of the print head presents problems relative to collecting the unused ink drops. Because of the rapid change in velocity of the print head unused drops deflected toward the ink drop collector may miss the collector to become deposited on the print medium or on the support structures, thereby fouling the machine apparatus.